The pump actuator is an important part of the automobile engine using high-pressure fuel pump system, and is mounted between the driving cam and the tappet to transform the rotational motion of the driving cam into the linear reciprocating motion of the tappet. The main structure of the pump actuator includes a shell, a holder, a roller and a pin.
The existing guide sleeve of high-pressure fuel pump actuator is a housing which is in a shape of a cylinder, which is made from the complex cold forming process. The mechanical manufacturing cost is high, which lead to a high cost of the tappet. Also, the efficiency of using the material cannot be optimized. The guide sleeve and the holder are formed together by forging. Thus, the lateral force acting on the holder will transmit to the guide sleeve from the driving cam, which causes the vibration of the guide sleeve inside the cylinder. This will damage the cylinder and the guide sleeve. Moreover, the guide block on the side of the guide sleeve which is used for restraining the axial rotation of the pump actuators is a structure in which the guide block embeds in the housing. Thus, the manufacture and assembly process is more complex.